I think public transit would only be viable in dense urban cores. In other areas, if the city desires to provide transportation assistance, I think it's probably more efficient to provide other forms of transportation to the working poor (who are typically the primary users of public transit in midsized cities). Here in Grand Rapids, the busses are so lightly used that it would probably be cheaper for the city to hand out Uber or Lyft credits for the people that are now using the busses (and it'd provide a better user experience too).